fix(ci_visibility): set up Test Optimization logging before pytest log capture (#13030)

We have a recurring problem where emitting logs at the end of a pytest
test session results in errors like:
```
Traceback (most recent call last):
  File "/usr/local/lib/python3.10/logging/__init__.py", line 1103, in emit
    stream.write(msg + self.terminator)
ValueError: I/O operation on closed file.
```
This happens because our plugin calls
`take_over_logger_stream_handler()`, which calls
`logging.StreamHandler()`, which defaults to using `sys.stderr` as its
output stream, but by the time we call it, pytest's
[`pytest_load_initial_conftests` hook from
`capture.py`](https://github.com/pytest-dev/pytest/blob/8.3.x/src/_pytest/capture.py#L155)
has already executed and replaced `sys.stderr` with a `FileIO` buffer
that is closed by the end of the test session, so we grab a reference to
this internal `FileIO` buffer instead of the actual `sys.stderr`. This
PR makes our own `pytest_load_initial_conftests` hook run earlier than
pytest's `capture.py` one.

Additionally, this fixes `take_over_logger_stream_handler()` to copy the
handler list before calling `removeHandler()`, as this mutates the list
we are iterating through.

One user-visible side effect of this is that now we always print these
logs at the beginning of the test session, regardless of whether `pytest
-s` is used:

```
[Datadog CI Visibility] INFO     ddtrace.internal.ci_visibility.recorder:recorder.py:294 Service: vitor-test (env: some-env)
[Datadog CI Visibility] INFO     ddtrace.internal.ci_visibility.recorder:recorder.py:295 Requests mode: agentless
[Datadog CI Visibility] INFO     ddtrace.internal.ci_visibility.recorder:recorder.py:296 Git metadata upload enabled: True
[Datadog CI Visibility] INFO     ddtrace.internal.ci_visibility.recorder:recorder.py:297 API-provided settings: coverage collection: False
[Datadog CI Visibility] INFO     ddtrace.internal.ci_visibility.recorder:recorder.py:298 API-provided settings: Intelligent Test Runner: False, test skipping: False
[Datadog CI Visibility] INFO     ddtrace.internal.ci_visibility.recorder:recorder.py:303 API-provided settings: Early Flake Detection enabled: True
[Datadog CI Visibility] INFO     ddtrace.internal.ci_visibility.recorder:recorder.py:307 API-provided settings: Auto Test Retries enabled: True
[Datadog CI Visibility] INFO     ddtrace.internal.ci_visibility.recorder:recorder.py:308 Detected configurations: {'os.architecture': 'x86_64', 'os.platform': 'Linux', 'os.version': '6.5.0-1027-oem', 'runtime.name': 'CPython', 'runtime.version': '3.10.14'}
[Datadog CI Visibility] WARNING  ddtrace.internal.ci_visibility.recorder:recorder.py:313 CODEOWNERS file is not available
[Datadog CI Visibility] INFO     ddtrace.internal.ci_visibility.recorder:recorder.py:628 Unique tests fetched for Early Flake Detection: 34
[Datadog CI Visibility] INFO     ddtrace.internal.ci_visibility.recorder:recorder.py:576 Final settings: coverage collection: False, test skipping: False, Early Flake Detection: True, Auto Test Retries: True, Flaky Test Management: True
```

Whether this is a bug or a feature is up to discussion. Previously we
only printed this if `pytest` was called with `-s`, more by accident
than by design.

The way I managed to reproduce it was by raising an exception right
after tracer shutdown in `CIVisibility._stop_service()`:

```
    def _stop_service(self) -> None:
        ...
        try:
            self.tracer.shutdown()
            raise Exception("ꙮ")  # <--- added here
        except Exception:
            log.warning("Failed to shutdown tracer", exc_info=True)
```

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

Author: vitor-de-araujo

ddtrace/contrib/internal/pytest/_plugin_v2.py

@@ -190,7 +190,18 @@ def _disable_ci_visibility():
         log.debug("encountered error during disable_ci_visibility", exc_info=True)
 
 
+@pytest.hookimpl(tryfirst=True, hookwrapper=True)
 def pytest_load_initial_conftests(early_config, parser, args):
+    """Perform early initialization of the Test Optimization plugin.
+
+    This has to happen early enough that `sys.stderr` has not been redirected by pytest, so that logging is configured
+    properly. Setting the hook with `tryfirst=True` and `hookwrapper=True` achieves that.
+    """
+    _pytest_load_initial_conftests_pre_yield(early_config, parser, args)
+    yield
+
+
+def _pytest_load_initial_conftests_pre_yield(early_config, parser, args):
     """Performs the bare-minimum to determine whether or ModuleCodeCollector should be enabled
 
     ModuleCodeCollector has a tangible impact on the time it takes to load modules, so it should only be installed if

ddtrace/internal/ci_visibility/utils.py

@@ -117,7 +117,7 @@ def take_over_logger_stream_handler(remove_ddtrace_stream_handlers=True):
     if remove_ddtrace_stream_handlers:
         log.debug("CIVisibility removing DDTrace logger handler")
         ddtrace_logger = logging.getLogger("ddtrace")
-        for handler in ddtrace_logger.handlers:
+        for handler in list(ddtrace_logger.handlers):
             ddtrace_logger.removeHandler(handler)
     else:
         log.warning("Keeping DDTrace logger handler, double logging is likely")

releasenotes/notes/ci_visibility-fix-io-operation-closed-file-1e1089eabd5296ce.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    CI Visibility: This fix resolves an issue where an ``I/O operation on closed file`` error was raised while printing
+    ``ddtrace`` logs during a pytest session, due to a conflict with pytest's log capture.